The lattice stitch is a suture-based method of surgical repair that distributes biologic tissue tension throughout the full thickness of the wound in both parallel and perpendicular directions from the wound edge. It is ideally, but not exclusively, suited for closure of atrophic skin and wounds under high tension and can be effectively used as a salvage stitch to repair wounds with secondary tissue tears (tears in wounds that have occurred as a result of failure of a wound repair using a closure other than the lattice stitch).
The lattice stitch is formed by first placing a pair of “anchor” stitches in opposed positions parallel to the wound edge, one on each side of the wound. The anchor stitches are placed with sufficient tension to minimize slack, while avoiding excessive tightening/strangulation of the skin. Next, a “closing” stitch is passed through the skin and is looped around the anchor stitches. The closing stitch is then drawn together at the surface of the tissue and is tied at the center of the wound. It is possible to place multiple closing stitches around a single pair of anchor stitches for additional support of the repair, at the surgeon's discretion.
In a lattice stitch repair, the closing stitch is preferably looped completely around each anchor stitch within the tissues, before the stitch is tied at the surface of the wound, thus, drawing the wound together to a closed condition. This arrangement optimizes stitch function and efficacy. Alternate arrangements of the closing stitch and anchor stitches in a lattice stitch repair include those where the closing stitch is passed through the loop of one or both anchor stitches, in the tissues, before the closing stitch is tied at the surface of the wound. Said alternate lattice stitch arrangements are not as effective at displacing wound tension or shear, in comparison to the preferred embodiment of the lattice stitch repair.
In the preferred embodiment of the lattice stitch, closing tension across the wound borne by the closing stitch is distributed away from the plane of closure in a direction parallel to the wound edge throughout the full thickness of the repair by the anchor stitches through a process called “dynamic vectoring.” In this process, the lattice stitch adjusts its three dimensional structural configuration to accommodate forces acting on the repair during wound closure and throughout the healing period. Tissue shear forces during closure of a lattice stitch are largely avoided since the closing stitch is drawn primarily over anchor stitches during closure. Leverage for the closure is provided for the closing stitch by the anchor stitches which act as fulcrums, allowing a great degree of force to be exerted on the closure with little effort. Unlike staples, the lattice stitch can be placed at significantly variable distances from the wound edge and can use substantial subcutaneous tissue support, depending on the needs of the closure. Suture removal is easy because the stitch does not “sink” into the skin; a common problem with the vertical mattress type closures typically used in high tension wound repairs. The lattice stitch is versatile and can be used singly as a support element in repairs where other stitching methods are used, or in plurality as part of a complex lattice closure in cases where a greater distribution of tension is desired.
Despite the stated advantages of the lattice stitch, there are some limitations of this repair technique. The anchor stitches of a lattice stitch must be properly tensioned for optimal function, and this can be difficult to achieve under certain conditions. Use of an “instrument tie” with the help of an assistant, can facilitate proper tensioning of the anchor stitches, but can be a challenge to arrange in a busy office or emergency room setting. Excessive tension in the anchor stitches inhibits optimal functioning of the lattice stitch and may contribute to wound ischemia. Slack anchor stitches, on the other hand, can lead to unnecessary stretching of the tissue behind the anchors when the closing stitch draws the wound together and can lead to small tissue tears behind the anchors by the closing stitch, especially in repairs of extremely delicate tissue. Pressure from the lattice stitch on the surface of the skin, especially in high-tension closures, might lead to the formation of scar tissue under the sutures (“suture tracks”). Although this problem is not unique to the lattice stitch, it could be seen more commonly with this method of repair since the lattice stitch is well suited for high-tension closures.
A need exists, therefore, for a device that can facilitate proper tensioning of the (lattice) anchor stitches without the need for an assistant/instrument tie whilst preserving the dynamic vectoring properties of the lattice stitch; and, to separate the suture material of the lattice stitch from the surface of the tissues to help reduce the likelihood of scarring. The device should also manage any frictional and rotational forces in a lattice stitch repair that can occur as the closing stitch draws the wound to a closed condition.
Various apparatus and suture based methods for biologic tissue repair are known in the patented prior art as evidenced by Bonutti U.S. Pat. No. 5,403,348; Bonutti U.S. Pat. No. 5,549,631; and Gibson U.S. Pat. No. 6,063,106.
Bonutti U.S. Pat. No. 5,403,348 discloses an apparatus that is adapted to be received at least partially in body tissue, for purpose of securing a suture in the body, consisting of a cylindrical tissue anchor with a smooth outer surface, and an attached suture means. Bonutti U.S. Pat. No. 5,549,631 is a continuation of Bonutti U.S. Pat. No. 5,403,348 that teaches a method for closing a discontinuity in biologic tissue by moving the tissue anchor described in Bonutti U.S. Pat. No. 5,403,348 into the body tissue by means of a pusher mechanism and an application of force. The anchor must be suitable for implantation in the biologic tissue and must be sufficiently rigid to permit suture retention function and according to the methods governing use of the anchor. The Bonutti method teaches a technique of skin repair that requires subcutaneous access to the wound and a high tolerance of tissue shear at the tissue insertion point of the apparatus at closure. The Bonutti method would not be suitable for applications where use of an implantable anchor device with an associated suture means was inappropriate or unnecessary; in repairs of delicate tissue; in situations where sufficient subcutaneous access to a cutaneous wound was unavailable, or in situations where a pusher mechanism as taught by Bonutti were unavailable.
The Gibson patent teaches a substantially disk shaped tissue spacer including a plurality of apertures for receiving suture thread and a depression in the bottom surface thereof to space the apertures above the surface of the skin to reduce the formulation of granulation tissue in surgical applications such as removal of varicose veins, treatment of chronic ulcerations and hernias, attachment of deep cutaneous structures and positioning of prosthesis under the skin. A disk shaped structure of a design consistent with the Gibson spacer would be incompatible with lattice stitch repair. Such a design would be significantly inflexible in the trans-axial plane (force applied on plane to the edge of the disk) and force applied perpendicular to the edge of the disk structure would result in a rotational stress on the structure, thus limiting use of such a design in applications such as lattice stitch repairs where such properties would be undesirable.
While the prior apparatus and methods operate satisfactorily as intended, they are not particularly effective in repairs involving lattice stitch closures of atrophic tissues, wide wounds, and/or delicate/high tension wounds with limited subcutaneous access, all of which require a reduction of tissue shear forces, accommodation of dynamic vectoring of tissue tension, and management of rotational and frictional force in the repair, in order to avoid tissue tears, ischemia, wound edge inversion, necrosis and/or dehiscence. The above apparatus and methods do not allow an unassisted surgeon to properly tension lattice anchor stitches whilst preserving the dynamic vectoring properties of the lattice stitch; and, by extension, cannot be used to separate the suture material of the lattice stitch from the surface of the tissues to help reduce the likelihood of scarring. The present invention was developed in order to overcome these and other drawbacks by providing a uniquely configured lattice stitch surgical tension-limiting device to complement lattice stitch repairs.